.TH GS 1 "21 September 2022" 10.00.0 Ghostscript \" -*- nroff -*-
.SH NAME
gs \- Ghostscript (PostScript and PDF language interpreter and previewer)
.SH SYNOPSIS
\fBgs\fR [ \fIoptions\fR ] [ \fIfiles\fR ] ...
.de TQ
.br
.ns
.TP \\$1
..
.SH DESCRIPTION
The \fBgs\fR
command invokes \fBGhostscript\fR, an interpreter of Adobe Systems'
\fBPostScript\fR(tm) and \fBPortable Document Format\fR (PDF) languages.
\fBgs\fR reads "files" in sequence and executes them as Ghostscript
programs. After doing this, it reads further input from the standard input
stream (normally the keyboard), interpreting each line separately and
output to an output device (may be a file or an X11 window preview,
see below). The
interpreter exits gracefully when it encounters the "quit" command (either
in a file or from the keyboard), at end-of-file, or at an interrupt signal
(such as Control-C at the keyboard).
.PP
The interpreter recognizes many option switches, some of which are described
below. Please see the usage documentation for complete information. Switches
may appear anywhere in the command line and apply to all files thereafter.
Invoking Ghostscript with the \fB\-h\fR or \fB\-?\fR switch produces a
message which shows several useful switches, all the devices known to
that executable, and the search path for fonts; on Unix it also shows the
location of detailed documentation.
.PP
Ghostscript may be built to use many different output devices.  To see
which devices your executable includes, run "\fBgs -h\fR".
.PP
Unless you
specify a particular device, Ghostscript normally opens the first one of
those and directs output to it.
.PP
If you have installed the ghostscript-x Debian package and are under X,
the default device is an X11 window (previewer), else ghostscript will
use the bbox device and print on stdout the dimension of the postscript file.
.PP
So if the first one in the list is the one
you want to use, just issue the command
.PP
.nf
	gs myfile.ps
.fi
.PP
You can also check the set of available devices from within Ghostscript:
invoke Ghostscript and type
.PP
.nf
	devicenames ==
.fi
.PP
but the first device on the resulting list may not be the default device
you determine with "\fBgs -h\fR".  To specify "AbcXyz" as the
initial output device, include the switch
.PP
.nf
	\-sDEVICE=AbcXyz
.fi
.PP
For example, for output to an Epson printer you might use the command
.PP
.nf
	gs \-sDEVICE=epson myfile.ps
.fi
.PP
The "\-sDEVICE=" switch must precede the first mention of a file to print,
and only the switch's first use has any effect.
.PP
Finally, you can specify a default device in the environment variable
\fBGS_DEVICE\fR.  The order of precedence for these alternatives from
highest to lowest (Ghostscript uses the device defined highest in the list)
is:
.PP
Some devices can support different resolutions (densities).  To specify
the resolution on such a printer, use the "\-r" switch:
.PP
.nf
	gs \-sDEVICE=<device> \-r<xres>x<yres>
.fi
.PP
For example, on a 9-pin Epson-compatible printer, you get the
lowest-density (fastest) mode with
.PP
.nf
	gs \-sDEVICE=epson \-r60x72
.fi
.PP
and the highest-density (best output quality) mode with
.PP
.nf
	gs \-sDEVICE=epson \-r240x72.
.fi
.PP
If you select a printer as the output device, Ghostscript also allows you
to choose where Ghostscript sends the output \-\- on Unix systems, usually
to a temporary file.  To send the output to a file "foo.xyz",
use the switch
.PP
.nf
	\-sOutputFile=foo.xyz
.fi
.PP
You might want to print each page separately.  To do this, send the output
to a series of files "foo1.xyz, foo2.xyz, ..." using the "\-sOutputFile="
switch with "%d" in a filename template:
.PP
.nf
	\-sOutputFile=foo%d.xyz
.fi
.PP
Each resulting file receives one page of output, and the files are numbered
in sequence.  "%d" is a printf format specification; you can also use a
variant like "%02d".
.PP
You can also send output to a pipe.  For example, to
pipe output to the "\fBlpr\fR" command (which, on many Unix systems,
directs it to a printer), use the option
.PP
.nf
	\-sOutputFile=%pipe%lpr
.fi
.PP
You can also send output to standard output:
.PP
.nf
	\-sOutputFile=\-
.fi
or
.nf
	\-sOutputFile=%stdout%
.fi
.PP
In this case you must also use the \fB\-q\fR switch, to prevent Ghostscript
from writing messages to standard output.
.PP
To select a specific paper size, use the command line switch
.PP
.nf
	-sPAPERSIZE=<paper_size>
.fi
.PP
for instance
.PP
.nf
	-sPAPERSIZE=a4
.fi
or
.nf
	-sPAPERSIZE=legal
.fi
.PP
Most ISO and US paper sizes are recognized. See the usage documentation for
a full list, or the definitions in the initialization file "gs_statd.ps".
.PP
Ghostscript can do many things other than print or view PostScript and
PDF files.  For example, if you want to know the bounding box of a
PostScript (or EPS) file, Ghostscript provides a special "device" that
just prints out this information.
.PP
For example, using one of the example files distributed with Ghostscript,
.PP
.nf
	gs \-sDEVICE=bbox golfer.ps
.fi
.PP
prints out
.PP
.nf
	%%BoundingBox: 0 25 583 732
	%%HiResBoundingBox: 0.808497 25.009496 582.994503 731.809445
.fi
.SH OPTIONS
.TP
.BI \-\- " filename arg1 ..."
Takes the next argument as a file name as usual, but takes all remaining
arguments (even if they have the syntactic form of switches) and defines
the name "ARGUMENTS" in "userdict" (not "systemdict") as an
array of those strings, \fBbefore\fR running the file.  When Ghostscript
finishes executing the file, it exits back to the shell.
.TP
.BI \-D name = token
.TQ
.BI \-d name = token
Define a name in "systemdict" with the given definition.  The token must be
exactly one token (as defined by the "token" operator) and may contain no
whitespace.
.TP
.BI \-D name
.TQ
.BI \-d name
Define a name in "systemdict" with value=null.
.TP
.BI \-S name = string
.TQ
.BI \-s name = string
Define a name in "systemdict" with a given string as value.  This is
different from \fB\-d\fR.  For example, \fB\-dname=35\fR is equivalent to the
program fragment
.br
	/name 35 def
.br
whereas \fB\-sname=35\fR is equivalent to
.br
	/name (35) def
.TP
.B \-P
Makes Ghostscript to look first in the current directory for library files.
By default, Ghostscript no longer looks in the current directory,
unless, of course, the first explicitly supplied directory is "." in \fB-I\fR.
See also the \fBINITIALIZATION FILES\fR section below, and bundled 
\fBUse.htm\fR for detailed discussion on search paths and how Ghostcript finds files.
.TP
.B \-q
Quiet startup: suppress normal startup messages, and also do the
equivalent of \fB\-dQUIET\fR.
.TP
.BI \-g number1 x number2
Equivalent to \fB\-dDEVICEWIDTH=\fR\fInumber1\fR and
\fB\-dDEVICEHEIGHT=\fR\fInumber2\fR.  This is for the benefit of devices
(such as X11 windows) that require (or allow) width and height to be
specified.
.TP
.BI \-r number
.TQ
.BI \-r number1 x number2
Equivalent to \fB\-dDEVICEXRESOLUTION=\fR\fInumber1\fR and
\fB\-dDEVICEYRESOLUTION=\fR\fInumber2\fR.  This is for the benefit of
devices such as printers that support multiple X and Y resolutions.  If
only one number is given, it is used for both X and Y resolutions.
.TP
.BI \-I directories
Adds the designated list of directories at the head of the
search path for library files.
.TP
.B \-
This is not really a switch, but indicates to Ghostscript that standard
input is coming from a file or a pipe and not interactively from the
command line.  Ghostscript reads from standard input until it reaches
end-of-file, executing it like any other file, and then continues with
processing the command line.  When the command line has been entirely
processed, Ghostscript exits rather than going into its interactive mode.
.PP
Note that the normal initialization file "gs_init.ps" makes "systemdict"
read-only, so the values of names defined with \fB\-D\fR, \fB\-d\fR,
\fB\-S\fR, or \fB\-s\fR cannot be changed (although, of course, they can be
superseded by definitions in "userdict" or other dictionaries.)
.SH "SPECIAL NAMES"
.TP
.B \-dNOCACHE
Disables character caching.  Useful only for debugging.
.TP
.B \-dNOBIND
Disables the "bind" operator.  Useful only for debugging.
.TP
.B \-dNODISPLAY
Suppresses the normal initialization of the output device.
This may be useful when debugging.
.TP
.B \-dNOPAUSE
Disables the prompt and pause at the end of each page.  This may be
desirable for applications where another program is driving Ghostscript.
.TP
.B \-dNOPLATFONTS
Disables the use of fonts supplied by the underlying platform (for instance
X Windows). This may be needed if the platform fonts look undesirably
different from the scalable fonts.
.TP
.B \-dSAFER
Restricts file operations the job can perform. Now the default mode of operation.
.TP
.B \-dWRITESYSTEMDICT
Leaves "systemdict" writable.  This is necessary when running special
utility programs, but is strongly discouraged as it bypasses normal Postscript
security measures.
.TP
.BI \-sDEVICE= device
Selects an alternate initial output device, as described above.
.TP
.BI \-sOutputFile= filename
Selects an alternate output file (or pipe) for the initial output
device, as described above.
.SH "SAFER MODE"
.PP
The
.B \-dSAFER
option restricts file system accesses to those files and directories
allowed by the relevant environment variables (such as GS_LIB) or
by the command line parameters (see https://ghostscript.com/doc/current/Use.htm
for details).
.PP
SAFER mode is now the default mode of operation. Thus when running programs that
need to open files or set restricted parameters
you should pass the
.B \-dNOSAFER
command line option or its synonym
.BR \-dDELAYSAFER .
.PP
Running with NOSAFER/DELAYSAFER (as the same suggests) loosens the security
and is thus recommended ONLY for debugging or in VERY controlled workflows,
and strongly NOT recommended in any other circumstances.
.SH FILES
.PP
The locations of many Ghostscript run-time files are compiled into the
executable when it is built.
Run "\fBgs -h\fR" to find the
location of Ghostscript documentation on your system, from which you can
get more details. On a Debian system they are in \fB/usr\fR.
.TP
.B /usr/share/ghostscript/[0-9]*.[0.9]*/*
Startup files, utilities, and basic font definitions (where [0-9]*.[0.9]* is
the ghostscript version)
.TP
.B /usr/share/fonts/type1/gsfonts/*
More font definitions from the gsfonts package
.TP
.B /usr/share/doc/ghostscript/examples/*
Ghostscript demonstration files (if ghostscript-doc package is installed)
.TP
.B /usr/share/doc/ghostscript/*
Diverse document files (may need to install ghostscript-doc package)
.SH "INITIALIZATION FILES"
When looking for the initialization files "gs_*.ps", the files related to
fonts, or the file for the "run" operator, Ghostscript first tries to open
the file with the name as given, using the current working directory if no
directory is specified.  If this fails, and the file name doesn't specify
an explicit directory or drive (for instance, doesn't contain "/" on Unix
systems), Ghostscript tries directories in this
order:
.TP 4
1.
the directories specified by the \fB\-I\fR switches in the command
line (see below), if any;
.TP
2.
the directories specified by the \fBGS_LIB\fR environment variable,
if any;
.TP
3.
the directories specified by the \fBGS_LIB_DEFAULT\fR macro in the
Ghostscript makefile when the executable was built.
\fBGS_LIB_DEFAULT\fR is 
"/usr/share/ghostscript/[0-9]*.[0-9]*/lib"
on a Debian system where 
"[0-9]*.[0-9]*" represents the Ghostscript version number
.PP
Each of these (\fBGS_LIB_DEFAULT\fR, \fBGS_LIB\fR, and \fB\-I\fR parameter)
may be either a single directory or a list of directories separated by
":".
.SH ENVIRONMENT
.TP
.B GS_OPTIONS
String of options to be processed before the command line options
.TP
.B GS_DEVICE
Used to specify an output device
.TP
.B GS_FONTPATH
Path names used to search for fonts
.TP
.B GS_LIB
Path names for initialization files and fonts
.TP
.B  TEMP
Where temporary files are made
.SH X RESOURCES
Ghostscript, or more properly the X11 display device, looks for the 
following resources under the program name "Ghostscript":
.TP
.B borderWidth
The border width in pixels (default = 1).
.TP
.B borderColor
The name of the border color (default = black).
.TP
.B geometry
The window size and placement, WxH+X+Y (default is NULL).
.TP
.B xResolution
The number of x pixels per inch (default is computed from \fBWidthOfScreen\fR
and \fBWidthMMOfScreen\fR).
.TP
.B yResolution
The number of y pixels per inch (default is computed from
\fBHeightOfScreen\fR and \fBHeightMMOfScreen\fR).
.TP
.B useBackingPixmap
Determines whether backing store is to be used for saving display window
(default = true).
.PP
See the usage document for a more complete list of resources.  To set these
resources on Unix, put them in a file such as "~/.Xresources" in the
following form:
.PP
.nf
	Ghostscript*geometry:	 612x792\-0+0
	Ghostscript*xResolution: 72
	Ghostscript*yResolution: 72
.fi
.PP
Then merge these resources into the X server's resource database:
.PP
.nf
	% xrdb \-merge ~/.Xresources
.fi
.SH SEE ALSO
The various Ghostscript document files (above), especially \fBUse.htm\fR. 
On Debian you may need to install ghostscript-doc before
reading the documentation.
.SH BUGS
See http://bugs.ghostscript.com/ and the Usenet news group 
comp.lang.postscript.
.SH VERSION
This document was last revised for Ghostscript version 10.00.0.
.SH AUTHOR
Artifex Software, Inc. are the primary maintainers
of Ghostscript.
Russell J. Lang, gsview at ghostgum.com.au, is the author of 
most of the MS Windows code in Ghostscript.
